From: Andy Lutomirski <[email protected]> If something goes wrong with pagetable setup, vsyscall=native will accidentally fall back to emulation. Make it warn and fail so that we notice.
Signed-off-by: Andy Lutomirski <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: David Laight <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> --- arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++++ 1 file changed, 4 insertions(+) Index: tip/arch/x86/entry/vsyscall/vsyscall_64.c =================================================================== --- tip.orig/arch/x86/entry/vsyscall/vsyscall_64.c +++ tip/arch/x86/entry/vsyscall/vsyscall_64.c @@ -138,6 +138,10 @@ bool emulate_vsyscall(struct pt_regs *re WARN_ON_ONCE(address != regs->ip); + /* This should be unreachable in NATIVE mode. */ + if (WARN_ON(vsyscall_mode == NATIVE)) + return false; + if (vsyscall_mode == NONE) { warn_bad_vsyscall(KERN_INFO, regs, "vsyscall attempted with vsyscall=none");
